The present invention relates to a rotary weight filler which performs a filling operation while measuring a filled content of a vessel by weight measuring means.
A rotary weight filler generally comprises a plurality of vessel receptacles disposed around the outer periphery of a revolving body at an equal circumferential spacing, a plurality of load cells (weight measuring means) mounted on the revolving body and connected to respective vessel receptacles for measuring the weight of a vessel placed on each vessel receptacle, filling means disposed above respective vessel receptacles, and control means for controlling the opening/closing of a filling valve of each filling means, and the arrangement is such that while vessels, which are placed one each on the vessel receptacle, are rotatively conveyed as the revolving body revolves, the tare of a vessel is measured by the load cell, and the filling valve is opened in response to a command signal from the control means to initiate filling a liquid into the vessel.
In a conventional rotary weight filler, the tare of the vessel supplied is measured before the filling valve is opened to initiate a filling operation. Immediately after the vessel has been supplied, the attitude of the vessel is yet unstable and the load cell may be subject to oscillation, preventing the measurement of the weight of the vessel from being performed until the vessel becomes stabilized. Accordingly, it takes a length of time until the tare of the vessel supplied is measured. The control means delivers a fill initiate command signal after the vessel has been supplied and its tare has been measured, and the filling valve is then opened to allow a filling operation to be actually initiated.
To accommodate for this, a rotary weight filler has been proposed (Japanese Laid-Open Patent Publication No. 2002-104303) which allows a fill initiate command signal to be delivered after the vessel has been supplied, but before beginning the measurement of the tare in order to allow the filling operation to be initiated as soon as possible after the completion of the measurement of the tare.
In the rotary weight filler disclosed in this citation, the fill initiate command signal is delivered before beginning the measurement of the tare, and accordingly, it is possible to open the filling valve to initiate the filling operation immediately upon completion of the measurement of the tare, thus allowing a filling interval to be increased in length. Nevertheless an interval to measure the tare of the vessel is still necessary even in this filler, there is a limit on the length to increase the filling interval.